In 1926 The Underground Group commissioned 55 Broadway, over St James's Park station, as its new headquarters. It was to replace Electric Railway House, whose offices were too cramped for the growing organisation. The headquarters was to symbolise the company's vision of public transport being at the heart of London's social and commercial life.
Frank Pick, assistant managing director of the Underground Group, commissioned the architect Charles Holden of the firm Adams Holden and Pearson to design the building. On its completion in 1929, 55 Broadway was the tallest building in London. However, building restrictions prevented the floors above the seventh being used as offices.

The modern and assertive design was considered an architectural masterpiece. It was awarded the London Architectural Medal by the Royal Institute of British Architects in 1929. The Underground Group's desire to make a bold architectural statement in keeping with the ideals of the company had been realised. The commission was based on Holden's previous work for the Underground Group on the Northern line extension Underground stations, including Morden and Clapham South. Both Pick and Holden shared the same philosophy in architecture, that it should be well designed and easy to use. They wanted to produce buildings with clean simple lines, proclaiming their 'fitness for purpose'.

The building is Portland stone over a steel structure. Holden's response to the site, which was an awkward diamond shape, was an inspired cruciform plan. Open plan offices radiate in four wings from a central tower. Large expanses of glass make the most of the direct natural sunlight. There are no internal light wells as was common in buildings of this size. The offices are partitioned with Muranese glass that lets in light but can be moved as necessary. This plan followed contemporary American office design, but was considered an innovation in London. Some of the ground floor offices were lit by top light.

Holden also designed the furniture in the senior executives' offices. The interior corridors are lined with Italian Travertine marble on the floors and walls. The marble has irregular crevices that give it a non-slip effect, but also make it more difficult to clean.
The whole, set on a two-storey podium, makes a striking silhouette. The seventh, ninth and the tenth storeys are stepped back to the 53 m.(175-ft.) tower in the centre. The tower has four further floors, topping the central shaft where the lifts, staircases and toilets are situated. The exterior of the building is sparsely decorated. It has circular grey granite piers with square black marble capitals on the ground floor, which look similar to classical columns. The only other exterior decoration is the relief sculptures.

Holden commissioned some of the most famous sculptors of the day to carve large figurative reliefs, depicting the four winds, directly onto the stonework. These are high up each side of the four wings. The sculptors were Eric Gill, Henry Moore, Eric Aumonier, Samuel Rabinovitch, Allan Wyon and Alfred Gerrard. Holden commissioned Jacob Epstein to create two groups over the entrances called 'Day' and 'Night'. Their primitive, vital style and the figures' nudity created a furore. Both Pick and Holden stood by the sculptor, Pick even tendering his resignation in support of Epstein. His resignation was not accepted and the sculptures stayed. However an inch and a half had to be removed from the penis of the figure in 'Day', as the original size offended contemporary sensibilities.

Epstein's sculptures were not universally slated. One contemporary commentator wrote, 'When one looks at them one hardly likes them, but they make such a powerful impression on the mind that when one has left the building they stand out in the memory and seem vividly to symbolise their subjects'. The same commentator went on to say 'one would be happier if all buildings were as good as this'.

In the 1980s the ground floor of the building was redesigned to create a new, improved reception area and a shopping mall. 55 Broadway is now a Grade II listed building.